Manufacture of mixed textiles



Patented May 4, 1943 MANUFACTURE OF MIXED TEXTILES Gilbert I. Thurmond an Asheville, and Edward d James W. Jacokes,

Brenner, Hendersonville, N. 0., assignors to American Enka Corporation, Enka, N. C., a corporation of Delaware No Drawing. Application May 13, 1940, Serial No. 334,994

5 Claims.

The present invention relates to the manufacture of continuous filaments, staple fiber, films and the like, and more particularly to the production of filamentous threads formed from cellulose-protein mixtures.

It is generally known at present that efforts to prepare stable cellulose-protein mixtures such as viscose-casein, have been commercially unsuccessful. In attempting to produce spinning solutions of. this type, various problems have arisen causing difllculties that, up to the present, have rendered the use of the solutions impractical. Prior practice involving bringing together viscose and casein resulted in the partial precipitation of either the cellulose or protein, and if normal precautionary measures were taken to avoid such precipitation, a proper dispersion of the protein was not efi'ected, the particles being non-uniform and heterogeneously distributed. One of the most serious drawbacks in using casein-viscose mixtures, has been that the protein content was not retained in the thread during coagulation and subsequent washing and other textile treating operations. This defeated the primary purpose of utilizing such mixtures, namely, substantial retention of the tensile strength due to the cellulose content while imparting to the thread the protein property of afiinity for acid dyes similar to that of natural wool. When the protein content is removed from the thread, it lowers the tensile strength and renders it unsatisfactory from the standpoint of dyeing with wool. Heretofore, cellulose-protein threads could not, therefore, be used in combination with natural wool as the mixed fibers could not be dyed uniformly.

It is the object of the present invention to form stable cellulose-protein mixtures that can be extruded to provide a product having substantially the same strength of cellulose while exhibiting the acid-dyeing properties of proteins.

It is a further object of the invention to'manufacture viscose-casein threads and the like wherein the protein content is retained during subsequent textile treating operations, or at least the protein content is controlled to impart the desired characteristics to the finished thread.

The invention further contemplates the pro duction of continuous filaments or staple fibers which may be used alone or mixed with other fibers, particularly wool, and dyed uniformly therewith.

Another object of the invention is the provision of an improved process in which the variable factors in the spinning system are predetermined and adjusted in order to eifect a stable viscose-casein product.

An additional object contemplates utilizing dispersing agents that will eifect a uniform and homogeneous distribution of the protein and cellulose content in the spinning solution.

Other objects, such as maintaining the proper tension on the freshly formed threads during the spinning operation, controlling the composition of the coagulating bath, correspondingly adjusting the spinning conditions, etc., are comprehended by the present invention.

Referring now to the detailed process, the proper preparation of the cellulose solution and the protein solution and the mixing thereof, is highly important. Several methods which may be employed are as follows: (1) Dissolving cellulose xanthate in NaOH in the usual manner for the preparation of viscose, separately dissolving a protein such as casein, alpha protein from soy beans, zein from corn, etc., in a suitable solvent of the type KOH, NaOH, and NHiOH and then thoroughly mixing the two solutions; (2) mixing dry protein with alkali cellulose,

xanthating the mixture and then dissolving the same in the normal dilute alkali employed in the preparation of viscose; (3) dissolving protein in dilute alkali, mixing the same with alkali cellulose, xanthating the mixture and then dissolving in dilute alkali; (4) dispersing dry protein in viscose; (5) mixing dry protein with cellulose xanthate and dissolving the mixture in dilute alkali; (6) mixing cellulose xanthate with a protein solution and then adding suflicient dilute alkali to dissolve the cellulose xanthate. (Where the expression'dilute alkali" is used in the preceding methods, it is intended that the aqueous solution has a concentration of less than 7% alkali, such as NaOH.)

The preferred method is No. l, as it has been determined that the most homogeneous solution is prepared by utilizing the same. Either the cellulose xanthate or the protein will form a solution in dilute alkali, but when the two solutions are brought together, a solution is formed wherein some of the particles exist in colloidal suspension. In first preparing the protein solution, suflicient time must be allowed to permit the protein particles to be dissolved or uniformly dispersed and the size of the particles is preferably of the order of 1 mu or less. The time required is dependent upon the temperature, for example using casein at 20 C., 4 to 6 hours is necessary to effect a homogeneous solution or dispersion.

The time element in the dissolving, mixing and aging operations, is important because otherwise various factors impair the character of the ultimate dispersion and, therefore, detrimentally affect the spinning solution. For example, if the solution is aged too long, hydrolysis takes place. The cellulose and protein solutions should be mixed from 4'to 48 hours after the preparation of the protein solution, although satisfactory protein dispersions before mixing may be maintained for approximately days. Whereas, the protein solution may be mixed into the cellulosic solution, it is preferable to mix the cellulosic solution into the protein solution. In order to obtain a thorough and uniform dispersion, a circulating pump system is suitable.

The solution is filtered either prior to, or after mixin although it is preferable to filter the solutions separately and then mix. In any case, in order to deaerate the solution, it is kept under vacuum for some time after mixing.

The mixed solution is spinnable as long as the size of the dispersed protein particles does not exceed the diameter of the normal spinneret orifices, although spinning is improved and the properties of the product are better if the size of the particles are maintained at less than 1 mu. It has been determined that more protein is washed out as the size of the particles increases.

Unless counteracted, the tendency of the protein particles is to agglomerate (in protein-viscose mixtures). The addition of proper dis; persing agents to the mixture provides a more stable and homogeneous suspension that will not separate or agglomerate upon aging. In this way, the mixture may be aged or ripened to a NH4CI index from to 5, the preferred ripeness has an index of approximately 10. (The index is measured in terms of the cellulosic solution.) The dispersing agentmay be added to the protein solution or the cellulosic solution or to the mixture, although it is preferably added to the protein solution. The number of dispersing agents which have been found to be particularly adaptable may be divided into two general classifications, those which are surface active and those which are non-surface active.

The surface active agents include penetrants,

detergents and softeners, which will dissolve or disperse in cellulosic and/or protein solutions or their mixtures to change the interfacial tension at the cellulose-protein interface, and thereby permit a more stable dispersion. In this con nection, the following groups of compounds have been found useful:

(1) Sulfonated products of vegetable oils, fats, hydrocarbons:

Prestabit oil Sulfonated castor oil Monopol brilliant Sulfonated olive oil Turkey red oil Sulfonated teaseed oil Base A Sulfonated naphthalene (2) Quaternary ammonium compounds.(This includes compounds which have nitrogen in the ring and compounds withnitrogen in the chain.)

Lauryl pyridinium chloride Lauryl pyridinium sulfate Stearyl pyridinium chloride Allyl pyridinium chloride Dodecyl tri ethyl ammonium chloride Triton S Triton B Triton F Sodium octadecyl sul- (3) High molecular nitrogen 'bases and their salts:

(a) Aliphatic nature Sapamine A Sapamine CH Sapamine Ms Sapamine FL Sapamine KW (4) Suljated higher alcohols and t eir salts: Tergitol penetrant 08 Sodium oleyl sulfate Gardinol LS, and WA Avirol Sodium lauryl sulfate Tergitol penetrant 4,

and 7 (b) Cyclic or heterocyclic Sapamine BCH Fixanol fate (5) Amine and amide derivatives of substituted ethers and esters:

Igepon A Igepon T (6) Sodium alkyl aryl sulfonates:

Nacconal NRSF Solvadine NC Invadine B,D,N Aresket Areskap (7) Sulfonated ethers:

Triton 720 (8) Suljonated esters of dicarboxylic acids: Aerosol 0T protein solution to prevent possible putrefaction due to bacterial action. Examples of satisfactory preservatives are:

Dowicide B Phenol.

Chlorinated phenol derivatives Cresol Chlorinated cresol derivatives The cellulose-protein mixed solution is spun on the same type ofequipment and in a similar system as that normally used for spinning viscose thread or staple fiber. The thread may be spun with varying degrees of tension and collected on bobbins, reels, pots and the like or may be cut into staple fibers. It may then be treated for several hours in a formaldehyde solution, for

example 10% formaldehyde and 10% sodium sulphate. This hardening solution reduces the solubility of the dispersed protein which, therefore, will not substantially wash out of the thread in subsequent washing, desulphurizing and other textile operations, but this naturally involves an additional expensive operation. The thread spun in this manner has a high tensile strength due to the retention of the protein content therein. and may be dyed with either direct dyes or acid wool dyes.

The above mentioned formaldehyde treatment may be omitted and the desired properties in the finished thread still be retained if a higher stretch than that normally given is imparted to the thread prior to collection. In order to efiect the said higher stretch, it is necessary to adjust several other factors during the spinning process. The high stretch assists in retaining the protein content in the thread provided the variable factors are adjusted accordingly. The coagulation and regeneration of the cellulose must be such that a membranous skin is formed on the surface of the individual filaments and ruptures therein are so minute that the protein will not be dissolved out,

The most important variable factor is the acidsalt ratio of the coagulating bath, althou h the alkalinity of the mixed solution must also be taken into consideration. Moreover, these two variables are in turn dependent on the denier of the filaments. Less important variable factors include the temperature of the coagulating bath, the maturity of the spinning solution, the spinning speed and the percentage stretch. Percentage stretch is among the less important factors only in connection with the rate of coagu lation. In" connection with properties affected by orientation of micelles it is very important. If the skin on the surface of the filaments can be maintained during spinning as a substantially unbroken sheath (consisting principally of cellulose), it will serve to protect the protein content from the solvent action of subsequent treat- It will be readily apparent that if one variable factor is altered for spinning a particular mixed solution. the other variable factors will have to be correspondingly adjusted.

Several methods for imparting the high stretch to the thread may be utilized such as bymeans of two or more driven godets. or thread storage devices rotating at higher peripheral speeds and. about which the thread is caused to pass a multiplicity of times. These godets or rollers may be driven in coa ulatin baths, heated washing baths and other treating baths; or the godets or rollers may be located alternately in and out of said baths. This system may include the so-cailed two-bath system" wherein the thread is partly stretched n a coagulating bath and given an additional stretch in a hot water or hot salt solution.

It has been determined that marked losses of protein content occur in spinning high denier threads. i. e.. 600/120 or denier per filament. When spinning such heavier deniers without stretch. an upper critical ran e of acid (H2800 concentration occurs between 9.3% and 9.7% with a fixed salt concentration. Above 9.7%. the coa ulation and/or re eneration is too rapid and a major portion of the protein is dissolved out. When the same denier threads are stretched, for examp e from 35% to 45% durim. coagulation. the critical ran e of concentrations of H2504 increases, i.'e.. as much as 10.5% of acid may be employed without substantial loss of the protein content,

It will be seen from the above that the cel ulose-protein threads are hi hl sensitive to sli h: acid concentration variations in the coa ulating bath provided the salt concentration is fixed. the theory bein that high ac d concentrations cause mechanical rupturin at the surface of the filaments. In which case. the protein is substantially dissolved out, thereby weakening the thread and rendering the same inert to acid wool dyes Whereas. various ranges of ac d concentrations may be employed depending on the variable factors, such ranges can be quickly determined for each particular spinning operation. And if the coagulating bath is adjusted so that at the surface of the filaments a skin is formed during substantial stretch. a high strength celluloseprotein thread is produced that will absorb acid wool dye-stuffs in a manner comparable with that of wool-like fibers.

It is apparent that numerous suitable modifications of an operative process. may be readily devised by a. simple balancing of the several variables described herein as critical with respect to retention of protein in the product. In summary of the foregoing discussion it may be stated that an increase in any one of the following factors favors retention of protein:

1 concentration 6f b. Concentration of salt l bath temperature d. Cellulose concentration e. Alkalinity of spinning solution i. Ammonium chloride index of spinning solution g. Take-up speed 1 denier 1'. Stretch Given the pertinent values of an operative process. a person skilled in the art can readily devise a wide variety of other operative processes by correspondingly increasing one of the above factors to compensate for each decrease in another of them.

The ratio of the protein in the thread may vary from 0.1% to 99% based on the weight of the cellulose. However, it is usually practical to use from 15% to 35% protein.

Similarly, each of the other important factors discussed above may be varied over an. extremely wide range. provided that the said factors are mutually adjusted to insure retention of the protein. For best results, it is desirable that the values of said factors be maintained in. preferred ranges as defined here. Thus, the concentration of sulphuric acid in the bath is preferably within the range of 6% to 14%, while the salts may range from 12% to 30% and the bath temperature varied between 10 and 90 C. In addition to the preferred range cited above for casein concentrations it is advisable to so prepare the spinning solution that it has an alkalinity of 4% to 9% (calculated as NaOH) and an ammonium chloride index between 7 and 15. While the denier may vary from 1 to 6 per filament and-the stretch imparted to the filaments be any value not substantally greater than if the other factors are suitably adjusted, it has been found preferable to maintain the linear spinning speed at a va ue between 50 and 80 meters per minute.

Threads formed in accordance with the above process may be given after-treatments similar to those used in the manufacture of viscose, for example they may be washed. desulphurized, bleached and dried. They are preferably bleached w th a solut on containing one or more bleaching agents of the type H202. Nazoz. NazBO: and sulphites. The finishing treatment may also be similar to that used in the viscose process and the softenin or lubricat ng agents to be employed depend on the particular use to which the thread is to be put.

lating bath at 42 C. containing:

EXAMPLE I 36 kg. of casein are allowed to stand two hours in 108 liters of water. During this period of standing the mixture is intermittently agitated to insure complete wetting out. When the soaking is complete, 53 liters of 3.05% sodium hydroxide are added and mixed for one hour. The mixing can be efiected by means of a propeller type stirrer rotating from 150 to 200 R. P. M. During this operation 1630 c. c. of Prestabit oil are added plus a small amount of phenol. At this stage, the caseinate is more fluid than viscose but is sufliciently viscous to indicate relatively slow mixing. The mixing may be carried out in alkali resistant equipment although this is not necessary as there is only about 0.5% of free sodium hydroxide. After mixing for approximately an hour, the solution should stand for 6 to 8 hours until all particles are completely dissolved.

1300 liters of normal unripened viscose (6.7%

'is of approximately the same viscosity as the viscose per se. Care must be taken during the mixing operation to prevent air from entering as much as possible, and therefore reduce the deaeration time to a minium. The mixed solution may be filtered if found to be necessary on microscopic examination and after ripening for approximately 18 hours to an ammonium chloride index of 10, is ready to be spun. The solution is found to have an alkalinity of 5.9% calculated as NaOH.

The viscose-protein mixture is then spun through a coagulating bath and collected at 70 meters per minute while stretching 45% between two godets.

The coagulating bath contains:

Per cent H2804- 9 Salt calculated as Na2SO4 equivalent 23 Lauryl pyridinium chloride 0.03

The spinning bath temperature was 42 C. The

thread was subsequently treated in the normal way as a continuous filament or as staple fiber.

EXAlllPLE II Per cent H5804- 10.0 Salt calculated as Na2SO4 equivalent 28.5 Lauryl pyridinium chloride 0.03

and collected at '10 meters per minute while stretching 45%.

EXAMPLE III The spinning solution of Example I is spun through a coagulating bath at 42 C. containing zinc sulphate to at least partially inhibit regen- The filaments are. withdrawn and passed through a bath of hot water at 75 C. while stretching 67% and collected at the rate of 70 meters per minute. The bundle of filaments may then be treated in any known manner.

Values of the several important variables in a number of processes found to produce caseinviscose threads are tabulated below in Table A. In this table, the column headings are similar to the reference letters given above in setting forth the tendencies toward retention, 1. e., as follows:

A. Concentration of H2804 (percent by weight) B. Concentration of salt calculated as NazSOr equivalent (percent by weight) C. Bath temperature (degrees centigrade) D. Cellulose concentration calculated as percent by weight of cellulose in total spinnable solids of spinning solution E. Alkalinity of spinning solution (percent alkali hydroxide) F. Ammonium chloride index of spinning solution G. Take-up speed (meters per minute) H. Denier per filament I. Stretch, expressed as percent TABLE A A B o D E F o n r ample Per Per Per Per Per cent cent C. cent cent M421". cent 1..... 10. 0 24. 0 43 75 5. 9 10. 0 71 5 45 2 7.0 22.0 43 75 5.9 10.0 71 3 0 3"--- 0. 5 24. 0 50 80 5. 9 12. 0 71 2 4--. 9.0 24. 0 75 5. 9 10. 0 80 3 25 5.-- 9.0 24.0 20 80 5.9 12.0 70 3 6"--- 6.0 20.0 45 75 5.9 11.0 70 1.5 15 7. 8.0 24.0 40 75 5. 0 10.0 70 2.0 35 8..-" 0.0 26.0 45 85 5.0 l2.0 70 3 45 9--- 10. 0 30. 0 40 75 6. 0 12. 0 75 1. 5 45 10. 8.0 28.0 75 6.0 12.0 70 1.0 0

The following Table B shows the characteristics of processes in which material amounts of casein were lost from the thread.

TABLE B A B o n E F o n r ample Per Per Per JtLpsm. Per cent C. can! cent cent 20.0 20 15 5.0 8.0 00 5 0 .0 23.0 40 75 5.0 10.0 10 3 10 .s 21.0 43 15 0.0 0.0 05 5 0 .8 21.0 40 75 5.5 10.0 40 5 10 0 220 50 10 5.0 9.0 50 4 20 11.0 22.0 '10 05 5.0 10.0 5 25 10.5 21.0 45 75 5.5 6.0 10 5 15 10.0 20.0 30 5.5 a0 60 4 10 0"..- 0.5 20.0 25 10 5.0 7.0 5 0 10.-.. 12.5 22.0 45. 75 0.0 1.5 50 0 10 What is claimed is:

1. A process for the manufacture of threads, staple fiber, films and the like from cellulose--pro-' tein mixtures which comprises mixing a viscose solution with an alkaline protein solution, adding a dispensing agent to effect a stable mixture containing highly dispersed particles of less ,than 10 mu, extruding the mixture into a coagulating bath containing 9 to 10% sulphuric acid and 23 to 30% salts of the class consisting of sodium sulphate, magnesium sulphate and zinc sulphate (calculated as sodium sulphate equivalent), to effect the formation of a skin on the formed product during subsequent stretching and then stretching the product at least 25% and aftertreating the same whereby the protein content is substantially retained therein.

2. A process for the manufacture of threads,

staple fiber, films and the like from cellulose-protein mixtures which comprises mixing a viscose solution with an alkaline protein solution, adding a dispersing agent to effect a stable mixture containing highly dispersed particles of less than mu, extruding the mixture into a coagulating bath having a temperature of about 42 C., and containing 9 to 10% sulphuric acid and 23 to 30% salts of the class consisting of sodium sulphate, magnesium sulphate and zinc sulphate (calculated as sodium sulphate equivalent), to effect the formation of a skin on the formed product during subsequent stretching and then stretching the product atleast aftertreating the same and collecting at about 70 meters per minute whereby the protein content is substantially retained therein.

3. A process for the manufacture of threads, staple fiber and the like containing characterizing amounts of cellulose and protein from cellulose-protein mixtures which comprises substantially the following steps: mixing 36kg. of casein dissolved in an aqueous solution of sodium hydroxide with 1300 liters of viscose solution containing 7.9% cellulose, effecting a stable mixture containing highly dispersed particles having an alkalinity of 5.9% calculated asNaOH, aging the solution for approximately 18 hours to an ammonium chloride index of 10, extruding the solution into a coagulating bath having a temperature of 42 C., and containing 9% sulphuric acid and 23% salt (calculated as sodium sulphate equivalent) withdrawing and stretching the coagulated material 45% and collecting the same at a speed of 70 meters per minute.

4. A process for the manufacture of threads, staple fiber and the like containing characteriz- 5 ing amounts of cellulose and protein from cellulose-protein mixtures which comprises substantially the following steps: mixing 36 kg. of casein dissolved in an aqueous solution of ammonium hydroxide with 1300 liters of viscose solution containing 7.9% cellulose, effecting a stable mixture containing highly dispersed particles having an alkalinity of 5.9% calculated NaOH, aging the solution for approximately 18 hours to an ammonium chloride index of 10, extruding the solution into a coagulating bath having a temperature of 42 0., containing 10.0% sulphuric acid and 28.5% salts (calculated as sodium sulphate equivalent) withdrawing and stretching the coagulated material 45% and collecting the same at a speed of 70 meters per minute.

5. A process for the manufacture of threads. staple fiber and the like containing characterizing amounts of cellulose and protein from cellulose-protein mixtures which comprises substan- 25 tially the following steps: mixing 36 kg. of casein dissolved in an aqueous solution of sodium hydroxide with 1300 liters of viscose solution containing 7.9% cellulose. efiecting a stable mixture containing highly dispersed particles having an alkalinity of 5.9% calculated as NaOH, aging the solution for approximately 18 hours to an ammonium chloride index of 10, extruding the solution into a coagulating bath having a temperature of 42 C., and containing 9.25% sulphuri c acid, 17.25% sodium sulphate, 5% magnesium sulphate, 1% zinc sulphate, withdrawing and stretching the coagulated material 67% in a bath of hot water at a temperature of about 75 C. and collecting the same at a speed 'of 70 meters per minute.

' GILBERT I. THURMOND.

JAMES W. JACOKES.

EDWARD BRENNER.

CERTIFICATE OF CORRECTION. Patent No. 2, 18 May 1;, 19M.

- GILBERT I. wmmnoma, ET AL.

of the above numbered patent requiring correction as follows: Page 14., sec-- 0nd column, line 72, claim 1, for "dispensing" read --dispersing--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 8th day of June, A. D. l9LL5.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents. 

